Electrical pickups for musical instruments



Oct. 20, 1959 H. DE ARMOND ETAL 2,909,092 ELECTRICAL PICKUPS FOR MUSICAL INSTRUMENTS Filed Nov. 19, 1956 INVENTOR? Harry De Armand ATTORNEY United States vPatent ELECTRICAL PICKUPS FOR MUSICAL INSTRUMENTS Harry De Armond and Leonard N. Meeker, Toledo, Ohio, assignors to Rowe Industries, Toledo, Ohio Application November 19, 1956, Serial No. 623,232 Claims. (Cl. 841.15)

This invention relates to an improved "adjustable electromagnetic pick-up in which substantially permanent magnets, having a suitable surrounding electric coil, are employed for inducing the proper circuits for the loud speaker, the device being for use with musical instruments particularly of the stringed type.

An object of the present invention is to provide a greatly simplified adjustment for the separate permanent magnets of the pick-up device to properly vary the position of each magnet from the strings.

A further object of the present invention is to provide an adjustable electromagnetic pick-up device of the character indicated, in which the adjusting means between each magnet and the body portion of the pick-up device is carried by the magnet itself.

Another object of the present invention is to provide an adjustable magnet means which is inherently capable after adjustment of becoming set in any one position of adjustment without readily moving therefrom.

Further object and advantages are within thescope of this invention, such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements, per se, and to economies of manufacture and numerous other features, as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

Figure I illustrates the application of the improved electromagnetic pick-up to a guitar;

Figure II is an enlarged plan view of the pick-up assembly;

Figure III is a section taken substantially on the line III-III of Figure II;

Figure IV is an elevation line IVIV of Figure II Figure V is a bottom plan view of the pick-up assembly;

Figure VI is a section showing an alternate form of magnet construction; and

Figure VII is an enlarged section on the line VII-VII of Figure VI.

Figure I illustrates the application of the improved electromagnet 10 applied to a guitar and the lead out lines 11 are indicated as to be connected with a loud speaker. This electromagnetic pick up device is illustrated in section in Figure IV, where it will be seen that a molded insulating form or core body portion 12 is provided, having a base section 14, a top rectangular, flatwise extending section 15 connected by a reduced section 16 (see Figure VI). The body portion of the core 12 has a plurality of transverse openings 17 to receive the adjustable permanent magnets 18. A suitable coil 20 is wound around the reduced portion 16 of the insulator block 12, said coil 20 fitting between the peripheral flange li ke extensions indicated at 14 and the top section indicated at 15. As indicated in Figure H, this top section 15 may be formed into a pleasing design elfect by propartly in section along the ice viding a central elevated portion 21 with the curve tapered surfaces 22 and 23 as shown.

It is understood that one relatively permanent magnet 18 is arranged for each string of the instrument to which the device is applied, and it is desirable to adjust each magnet independently of the position of the other magnets to obtain the most harmonious and best results of an electric pick-up of this nature. To this end, the present invention provides adjustable means directly attached to the magnets themselves, so constructed and arranged that the same may be individually adjusted and held in correct position of adjustment. To this end the invention includes a transverse or base plate 25 provided with a plurality of screw-threaded openings 26 aligned with the openings 17 in the insulator block 12, and as will hereinafter appear the magnets 18 are screw threaded into these openings 26 and held in adjustable position. To this end we have provided as a suitable construction in the present invention means for clamping this bottom plate 25 to the insulator block '12 by a suitable framework construction 27, a top flange 28 of which is adapted to fit over the top section 15 of the insulator block 12 as shown.

Interconnected means are employed between the frame 27 and the base plate 25 by providing a plurality of .end angle pieces 30 extending upwardly from the base plate 25, said angle pieces 30 being provided with openings 31 therein. The frame 27 has a plurality of relatively short, inwardly extending projections 32 on the end portions thereof, adapted to snap into the holes 31 on the angle pieces 30 and clamp the insulating core 12 and parts between the base plate 25 and the top flange 28 of the frame 27.

As stated supra, the base plate 25 has a plurality of screw threaded openings 26 therein, and each of the substantially permanent magnets 18 is provided with screw threads surrounding the cylindrical portion thereof for adjustably mounting the magnets in said openings 26. An important feature of the present invention is the use of a substance such as cast nylon, forming the screw threads 33. This cast nylon 33 for each magnet is applied to the magnets 18 by a molding process in which the magnets are suitably supported in a form having screw threads therein and the nylon material is heated to become fluid whereupon it is poured into the form around said magnets. We provide a kerf 35 as shown in the magnets 18 so that said fluent nylon material 33 may completely extend into said kerf 35 so that upon cooling the nylon sleeve and threads 33 are firmly united to the magnets 18. We have found that by forming these screw threads and intimately securing the same to the magnets, the latter may be adjusted in the base plate 25, the nylon having the property of resisting tendency to move due to the increased amount of friction. This results in maintaining the magnets in a very accurate position of adjustment.

In Figure III is illustrated a transverse screw driver slot 36 for turning the magnet and screw threaded sleeve 33 for proper adjustment, whereas in Figure VI a modified form of adjustment element for this purpose is il lustrated in the cap 37 made of diflferent material from the magnet 18 but suitably secured thereto. This cap 37 has a transverse screw driver slot 38 as shown, by which the adjustments may be made. This cap 37 is found desirable since the material forming the magnet 18 is very hard and use in adjusting the same may cause chipping of the metal, whereas the cap 37 may be of softer steel, which will resist such action and yet form suitable means for turning the magnet and the threads 33.

What we claim is:

l. A substantially permanent magnet and adjustably positioning and retaining assembly for an electric pick up for stringed instruments, including a relatively hard metal substantially permanent magnet; a cylindrical sleeve formed of non-magnetizable material the external surface of said sleeve being provided with screw threads arranged to cooperate with a screw threaded supporting base in said pick up; means between said sleeve and said magnet to retain said magnet and sleeve in fixedrelative position; 1 said magnet being provided with means operatively' associated with said magnet whereby said sleeve and said magnet may be simultaneously adjusted,

2. A substantially permanent magnet and adjustably positioningand retaining assembly for an electric pick up for stringed instruments, including a relatively hard metal magnetic pick up mechanism for stringed instruments,

said means including a relatively thin metal base supporting member, said member having a transverse single screw threaded opening therein; a cylindrical sleeve' formed of nylon, the external surface of said sleeve being provided with screw threads to cooperate with said single screwthread in said base member; a substantially perma nent cylindrical magnet positioned within said sleeve, means between said sleeve and said magnet to retain said sleeve and magnet in fixed relative position; and means at one end of said magnet to adjust the position of said sleeve and magnet relative to said base member.

4. A substantially permanent magnet and adjustably positioning and retaining assembly for an electric pick up device for stringed instruments, said pick up having a core of insulating material having a transverse opening therein, and said core adapted to carry a coil positioned on the outer portion of said core, said assembly including a relatively hard metal substantially permanent magnet; a hollow cylinder of nylon forming a non-magnetizable sleeve around said magnet; the external surface of said sleeve being provided with screw threads and means securing said sleeve to said magnet to retain said sleeve and magnet in fixed relative position, said screw threaded sleeve arranged to cooperate with screw threads in said pick up device for adjustably retaining said magnet relative thereto.

5. In a magnetic pick up for stringed instruments having a plurality of separately adjustable relatively permanent magnets and an elongated core body forming an insulation portion with a circumferential recess therein; said core having a plurality of transverse openings therein, the transverse area of said openings being restricted for a distance below the face of said core adapted to be positioned toward the strings of the instrument, each of said transverse openings adapted to receive one of said adjustable magnets; an elongated thin sheet metal plate located along one face of said core, said plate having a plurality of screw threaded openings thereon, said openings having a single thread only and being positioned in alignment with said magnet receiving openings in said core, said plate adapted to support said magnets, each magnet having attached thereto a sleeve having screw threads on the outside of said sleeve to coact with the single thread in said base plate, the opposite ends of said plate having right angle resilient angle pieces adjacent the end walls of said core with openings in said angle pieces; a rectangular frame; an inturned flange around the edge of said frame adapted to fit around the edge of one face of said core; an outturned flange around the other edge of said frame, po-rtions of said frame between said inturned and outturned flanges providing means for contacting said angle pieces of said base plate upon assembly of said frame to said base plate, said frame having inwardly directed projections whereby when said flange member is placed in contact with said base member said projections snap into said openings on said resilient angle pieces to clamp said core and said magnets between said plate and said frame.

References Cited in the file of this patent UNITED STATES PATENTS 2,612,072 De Armond Sept. 30, 1952 2,612,541 De Armond Sept. 30, 1952 2,672,781 Miessner Mar. 23, 1954 

